This invention relates to a method of photographing on microfilm which permits simple imaging of additional information on microfilm for facilitating later retrieval thereof and the apparatus therefor.
As more and more information is needed in society, image processing technology is increasingly in demand for recording documents and reference materials in microfilm, retrieving them when necessary, and projecting the information in enlargement, or duplicating them in hard copy. FIG. 1 shows a widely used microfilm photographing apparatus wherein a camera 1 with a focusing lens 2 mounted on a supporting pole 3 moves up and down along the supporting pole 3 so as to include a manuscript (including documents, microfilm and so on) 6, placed on a table 7, within visional fields 4A and 4B. The camera 1 photographs the images at an appropriate magnification and focus to record the manuscript 6 microfilm frame by frame. Lights 5A and 5B, provided on both sides of the camera 1 and supported on a control box 8, are directed to the manuscript 6 so that the manuscript 6 is constantly illuminated with a given amount of light.
The microfilm recorded in the above manner should be stored in a systematic and easy-to-use manner to allow quick retrieval for effective use. In order to facilitate such systematic storage and later retrieval, it is necessary to record additional information in correspondence to each frame of images on the microfilm. Blip marks, serial numbers indicating frame number, dates of recording, etc. are generally used as such additional information which are conventionally provided on the table 7 at a location close to the manuscript 6 within the visual fields 4A and 4B. The additional information is photographed together with the manuscript 6. Figures in the additional information frame are replaced for recording images of each frame. This method, however, involves complicated operations such as replacing figures or characters for every recording. Morever, since the optical magnification changes depending on the size of manuscript or of film, the size of the recorded additional information of the microfilm becomes inconsistent if the characters of the same size are used. On the other hand, if the size of the characters is changed in correspondence to the size of manuscript, the operation becomes more complicated.
Another method has been proposed which rotates character gears interlockingly with the feeding of the microfilm in the camera 1 so that a serial number is photographed together with the manuscript. However, such character gears can be provided only at a predeterminded location in relation to the image frames, thereby presenting an inconvenience, especially when films of different sizes are used. The method has a disadvantage in that the character gears turn even if an unimaged frame is fed. Furthermore, since almost all retrieval apparatus has a fixed position on a frame for data for retrieval, one apparatus cannot be used universally for various types of retrieval apparatuses.